This invention relates generally to valve devices and freeze prevention systems for use with water hydrants, such as drinking fountains, emergency showers, eye wash stations, and the like. More particularly, this invention relates to an improved freezeproof valve assembly for maintaining water flow from a fountain or the like substantially constant when the fountain is turned on but insuring positive water drainage to a freezeproof position each time the fountain is turned off.
Water hydrant valve devices are well known of the type for draining water from within the hydrant to a position where it will not freeze when the hydrant is turned off. Typically, such valve devices include an on-off valve installed below the ground frost line and operated from above the ground by an elongated rigid actuator rod to control water flow from a buried water supply pipe to a hydrant standpipe having its upper end connected, for example, to the bubbler head of an outdoor drinking fountain or the like. A pressure-responsive relief valve is commonly associated with the on-off valve to confine water flow to the standpipe when the on-off valve is opended but to permit standpipe water to drain into the surrounding soil when the on-off valve is closed, thereby preventing water from remaining within the standpipe above the ground frost line where it might otherwise freeze.
A variety of problems and disadvantages are encountered with freezeproof valve devices of the type described above. For example, the elongated valve actuator rod must be custom-fitted to the particular buried depth of the on-off valve thereby substantially increasing the cost of hydrant installation. In addition, and perhaps more importantly, drainage valve malfunction can result in water failing to drain from the standpipe thereby presenting a substantial freezing hazard when the drainage valve sticks in a closed position. Alternatively, the drainage valve can stick in an open position thereby presenting a significant danger of siphoning potentially contaminated ground water into the standpipe for flow to the foundation bubbler head. Still further, in soil areas wherein the water table is unusually high, or wherein the soil is contaminated with certain types of pollutants, the water within the standpipe may not drain satisfactorily into the surrounding soil notwithstanding proper drain valve operation.
Several freezeproof valve arrangements have been proposed wherein standpipe communication with the surrounding soil is eliminated thereby avoiding the above-discussed problems associated with drainage into the surrounding soil. In many of these arrangements, water remaining within a standpipe when an on-off valve is closed is drained into an underground sump tank isolated from the surrounding soil and ground water. When the on-off valve is subsequently opened for hydrant operation, water flow to the standpipe is directed through a jet pump or the like adapted to draw water from within the tank for flow to the standpipe, thereby partially emptying the tank to accommodate subsequent drainage thereinto of water within the standpipe when the on-off valve is closed. However, in such systems, repeated opening of the on-off valve for short time periods can result in overfilling of the sump tank to prevent standpipe water from draining into the tank. In addition, when the on-off valve is held open for an extended time period, the sump tank water level can fall below the jet pump such that the combined standpipe water flow decreases substantially and becomes a mixture of water and air. Such flow alteration is highly undesirable and is particularly annoying with drinking fountains and the like in that the height and flow rate of a water stream projected from a bubbler head can drop substantially and unexpectedly while a person is taking a drink.
There exists, therefore, a significant need for an improved valve assembly for water hydrants, such as drinking fountains and the like, which provides positive isolation from ground water and surrounding soil, which protects the hydrant against freezing, and which provides substantially constant water flow during operation. The present invention fulfills these needs and provides further related advantages.